Conventional cattle feeds such as corn and alfalfa often fail to provide sufficient energy for cattle, especially lactating dairy cattle during periods of heavy milk production. Feed containing a high proportion of corn also has a tendency to depress the milk fat content of the milk produced by such cattle. Fat is a concentrated energy source, and it is known that if the proportion of fat in cattle feed is increased, lactating dairy cattle produce high milk yields without draining their reserves of body fat and without diminishing the proportion of milk fat in the milk produced.
However, it has been found that if the proportion of fat in the diet of cattle exceeds about 5% of the total feed solids, the feed has toxic effects upon the microorganisms in the rumen of the cattle. It appears that fat reduces the growth rate or even kills certain microorganisms which digest fiber in the cow's rumen, thereby lowering fiber digestibility. This deleterious effect on the cow's rumen is particularly true of unsaturated fats. Although the decreased fiber digestion in the rumen is partially compensated by greater fiber digestion in the lower parts of the alimentary canal, the total energy derived is less than that resulting from more complete microbial digestion in the rumen.
There has been a continuing need for new dietary supplements for animal feed which can be fed to ruminant animals without interfering with the rumen microorganisms, or being rendered ineffective by the rumen microorganisms.
U.S. Pat. Nos. 4,642,317; 4,826,694; 4,853,233; and 4,909,138 describe the incorporation of insoluble fatty acid salts in ruminant feed as a means of increasing the fat content of the feed without deleteriously affecting the ruminant digestion cycle. A feed additive such as fatty acid calcium salt functions as a rumen inert product which passes through the rumen without interfering with rumen fermentation (i.e., a rumen bypass product), and is subsequently metabolized in the abomasum or small intestine of the ruminant.
The fat content of a feed additive usually is derived from industrial tallow and oil byproduct source. Commercially available fat and oil byproducts are mixtures of long chain fatty acids or glycerides, or a combination of fatty acid and glyceride mixtures. The commercial fatty acid materials typically are discolored, and have a characteristic unpleasant rancid odor which are caused by the presence of volatile oxygenated organic compounds such as ketones and aldehydes. Malodorous carbonyl compounds which are contained in technical grade fatty acid sources are illustrated by methyl heptyl ketone, methyl nonyl ketone, butanal, heptanal, nonanal, deca-2-enal, deca-2,4-dienal, and the like.
Various methods of deodorizing fatty acid materials are described in U.S. Pat. Nos. 2,265,020; 2,715,642; 2,795,453; 3,052,701; 3,124,460; 3,471,536; 3,526,649; 3,895,042; 4,294,821; and 4,938,957. The methods generally involve contacting a bulk fatty acid material with an adsorbent such as activated bentonite, or extracting the fatty acid material with a solvent such as furfural.
There is continuing interest in the development of improved methods for deodorizing commercial fatty acid materials which have been designated for incorporation into animal feedstocks.
Accordingly, it is an object of the invention to provide a fatty acid salt composition which can function as a rumen bypass animal feed supplement, and permit a beneficial increase in the dietary fat content of the feed.
It is another object of this invention to provide a process for preparing a deodorized fatty acid salt ruminant feed supplement.
Other objects and advantages of the present invention shall become apparent from the accompanying description and examples.